Merge pull request rails#52465 from Shopify/sqlite-insert-returning

Get rid of unused `Sqlite3Adapter#use_insert_returning?`

Author: byroot

activerecord/lib/active_record/connection_adapters/sqlite3_adapter.rb

@@ -127,7 +127,6 @@ def initialize(...)
           results_as_hash: true,
           default_transaction_mode: :immediate,
         )
-        @use_insert_returning = @config.key?(:insert_returning) ? self.class.type_cast_config_to_boolean(@config[:insert_returning]) : true
       end
 
       def database_exists?
@@ -434,10 +433,6 @@ def shared_cache? # :nodoc:
         @config.fetch(:flags, 0).anybits?(::SQLite3::Constants::Open::SHAREDCACHE)
       end
 
-      def use_insert_returning?
-        @use_insert_returning
-      end
-
       def get_database_version # :nodoc:
         SQLite3Adapter::Version.new(query_value("SELECT sqlite_version(*)", "SCHEMA"))
       end